Electromechanical transducers are commonly used in connection with stringed musical instruments, especially in the bridge of electrically amplified guitars and the like. The most versatile configuration for a bridge pickup is that which produces independent string signals. This allows the sound of each string to be individually processed and also allows the sound of each string to be individually processed and also allows the instrument to control a second instrument such as a music synthesizer.
U.S. Pat. Nos. 3,712,951 issued to Rickard, 4,228,715 issued to Nourney, 4,314,495 issued to Baggs and 4,491,051 issued to Barcus describe arrays of pressure-sensing transducers in the bridge of acoustic guitars. Such pressure transducers typically provide hard mechanical coupling between the strings and the bridge or body of the instrument. The tone signals produced by such pickups typically suffer from a lack of dynamic range in the low frequencies, a transduction characteristic which tends to overbrighten loud string vibrations.
U.S. Pat. Nos. 2,222,057 issued to Benioff and 4,860,625 issued to Mathews describe arrays of cantilever beam transducers, each monitoring the vibrations of a vibrating string. Cantilever beams typically produce tone signals having a good dynamic range, but they are inherently more fragile than pressure transducers and they are prone to undesirable tuning-fork effects when hard-coupled to a common base. Such effects tend to produce undesirable cancellations in the pickup signal and also tend to increase string-to-string crosstalk in separate string signals, a most undesirable characteristic in polyphonic applications.
Proximity-sensing transducers which monitor a vibrating segment of the string are not as prone to spurious mechanical resonances as electromechanical pickups. Magnetic pickups of the type commonly used in stringed musical instruments are responsive to displacements of a ferrous string within the magnetic field of the pickup. The response of such magnetic pickups is an exponential function of the actual string displacement, a non-linear response characteristic which tends to enrich the harmonic content of the resulting tone signal and which also enhances its dynamic range in the low-frequencies.
Since the vast majority of musical instrument amplification systems are designed to process tone signals produced by conventional magnetic pickups and microphones, it appears preferable for electromechanical pickups to produce tone signals exhibiting comparable dynamic and timbral characteristics.
Additionally, since acoustic instruments are the models for their electric counterparts, it appears preferable for a pickup to generate and/or to enhance desirable acoustic tonal qualities in the host instrument.
It is therefore a first object of the present invention to provide an improved electromechanical pickup saddle capable of producing a harmonic enrichment in the vibrating string of a musical instrument by mechanical interaction therewith.
It is a second object of the present invention to provide an electromechanical pickup for producing tone signals emulative of those produced by electromagnetic pickups on acoustic instruments.
It is a third object of the present invention to provide an electromechanical transducer array exhibiting low string-to-string crosstalk for use in conjunction with polyphonic audio processing systems and pitch-detection devices.